U.S. patent number 5,768,893 [Application Number 08/649,188] was granted by the patent office on 1998-06-23 for turbine with internal heating passages.
Invention is credited to Simoes Raposo Bruges de Oliveira Manueljose, Kenzo Hoshino.
United States Patent |
5,768,893 |
Hoshino , et al. |
June 23, 1998 |
Turbine with internal heating passages
Abstract
Surfaces of the static blades of a turbine are heated by means
that a high temperature, high pressure working gas or heating gas
passes through inner passages formed inside the static blades, so
that the working gas which passes through interspaces defined
between adjacent ones of the static blades expands nearly
isothermally without a descent in temperature so as to boost an
output of the turbine.
Inventors: |
Hoshino; Kenzo (Hiratsuka-shi,
Kanagawa-ken, JP), de Oliveira Manueljose; Simoes Raposo
Bruges (Hiratsuka-shi, Kanagawa-ken, JP) |
Family
ID: |
12540806 |
Appl.
No.: |
08/649,188 |
Filed: |
May 17, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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377738 |
Jan 25, 1995 |
5557922 |
Sep 24, 1996 |
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Foreign Application Priority Data
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Jan 25, 1994 [JP] |
|
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6-038998 |
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Current U.S.
Class: |
60/682 |
Current CPC
Class: |
F01D
25/10 (20130101); F02C 3/36 (20130101); F02C
6/003 (20130101) |
Current International
Class: |
F02C
3/00 (20060101); F01D 25/08 (20060101); F01D
25/10 (20060101); F02C 6/00 (20060101); F02C
3/36 (20060101); F01D 025/08 () |
Field of
Search: |
;60/39.05,39.18,39.19,39.53,39.511,39.54,39.58,39.75,682
;415/114,115 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Casaregola; Louis J.
Attorney, Agent or Firm: Evenson, McKeown, Edwards &
Lenahan, P.L.L.C.
Parent Case Text
This application is a divisional of application Ser. No. 377,738,
filed Jan. 25, 1995, now U.S. Pat. No. 5,557,922, granted Sep. 24,
1996.
Claims
What is claimed is:
1. A turbine having an entrance, a heat exchanger where a heating
gas heats and reheats a working gas, said heat exchanger having a
heating element and a reheating element therein, and static blades
and dynamic blades, and interspaces defined between adjacent ones
of the static blades, said static blades having passages formed
inside the blades, an inlet to said passages, and an outlet from
said passages, a conduit to conduct said working gas from said
reheating element to said inlet, a conduit to conduct said working
gas from said outlet to said heating element, whereby the working
gas passes serially into each blade through its inlet, through the
passages thereof, and flows out through the outlet into said
heating element to be heated, a conduit to conduct the heated
working gas from said heating element to said turbine to then enter
the turbine through its entrance and feed into said interspaces to
thereby act on the dynamic blades of the turbine to rotate the
dynamic blades, and a conduit to conduct said working gas from said
turbine back to said reheating element to be reheated.
2. A turbine as defined in claim 1, wherein said conduit to conduct
said working gas from said turbine back to said reheating element
to be reheated further comprises a cooler and a compressor.
Description
FIELD OF THE INVENTION
The present invention relates to a turbine such as, for example, a
turbine used in a thermoelectric power generating plant.
BACKGROUND OF THE INVENTION
One example of a prior art electric generating turbine is shown in
FIG. 8, in which air is introduced as shown in direction 5 from an
inlet 4 to an axial flow compressor 1 to be compressed to a high
pressure and then fed into a combustion chamber 2 through an inlet
12 thereof, while the combustion chamber is fed with fuel through
another inlet 11. In the combustion chamber the combustion of fuel
with the compressed air generates working gas which is introduced
through nozzle 17 and static blades 15,15' to dynamic or running
blades 16 of the turbine, to drive the turbine shaft 8. The shaft 8
is connected to an electric generator 10.
FIG. 9 shows a system of a conventional turbine for an electric
power plant, in which working gas is introduced to the compressor 1
through an inlet 5 and is pressurized there. The compressed air is
brought into the combustion chamber 2 through the inlet 12 of the
passage 18, while fuel is fed into the combustion chamber 2 through
the inlet 11. Combustion gas having a high temperature and a high
pressure, which means the working gas, is introduced to the turbine
3 through the nozzle 17 to thereby rotate the rotor shaft 8 to
drive the load 10, and discharges through an outlet port 6. The
stator blades serve to change pressure energy of the gas to
velocity energy, and the dynamic blades change the velocity energy
of the gas to rotary motion energy of the turbine rotor, this
motion energy being changed to electric energy by means of the load
10. In this connection, work energy of the working gas is indicated
as an area ABCD in FIG. 11, wherein B means a state of air before
entering the combustion chamber, C means the state of the air when
it enters the stator blades from the combustion chamber, and D
means the state of the air when it flows out of the static blades.
It is thought that work quantity corresponding to the area ABCD
changes to velocity energy of the working gas.
FIG. 10 shows a system of an exemplified conventional, turbine of
the so called external combustion type (heated type) in which the
working fluid for driving the turbine is heated with a heating
fluid in a heating room. In this system, work energy of the working
fluid is represented as the area ABCD in FIG. 11.
In commonly accepted technique, in order to enlarge the above
mentioned area ABCD so as to obtain more electric energy through
the load (ex. generator), various means to increase the length BC
have been adopted. That means to elevate possibly the temperature
of C in comparison with the temperature of B by means of a
combustion room. Such an increase enlarges the specific volume. For
the purpose, heat-resisting materials used for the turbine have
been developed, whereby the temperature of C could be elevated. At
present, where the temperature of B is of room temperature, i.e.
nearly 300.degree. K (27.degree. C.), the temperature of C can be
elevated to 1600.degree. K. However, it will be appreciated that it
is not easy to elevate the temperature of C higher than that.
SUMMARY OF THE INVENTION
An object of the invention is to provide an improved turbine which
enables to generate electric energy more efficiently by means of
enlarging the above area ABCD without such elevation of the
temperature of C. In the turbine of our invention, working fluid
expands along an improved-expansion process CD" from the identical
temperature of C by improving the conventional expansion process
CD.
In order to attain the object of the invention, according to the
invention, a turbine mentioned below is provided. Namely, in a
turbine according to our invention described in claim 1, as shown
in FIG. 1, working gas,i.e. a high temperature, high pressure gas,
delivered from the combustion chamber 2 is introduced to a
collector pipe 19 through a nozzle 24, passes through an inlet 21,
inner passages 20 and an outlet 22 of static blades and is
introduced to the subsequent collector pipe 19 and then to the
subsequent static blades. The working gas which has finally entered
a collector pipe 19' by way of the interior of the first stage of
static blades passes through interspaces of the first stage of
static blades 15' from turbine inlet 25 thereby to be accelerated
therethrough, gets into the first dynamic blades 16', and flows
successively through static blades and dynamic blades of the
turbine to drive the turbine rotor. As shown in FIG. 2, the inner
passages 20 are arranged to extend in the static blades from the
inlet 21 of the inner passages through a pathway with a turn formed
inside the static blades to the outlet 22. This arrangement is
shown in FIG. 3, in which the gas passes from the compressor 1
through the combustion chamber 2 to static blades-heating means 26,
enters the turbine 3 from the heating means and discharges through
the outlet 6 thereby to drive the rotor shaft 8 and the load
10.
A turbine according to one embodiment has, in addition to the
turbine described in claim 1, a feature that working gas having
passed through the inner passages and the outlet of the static
blades is introduced to a recombustion chamber to be re-heated.
A turbine according to one embodiment, in an external combustion
turbine in which working fluid is heated with a heating fluid and
drives the turbine, has a feature that the heating fluid is
conducted to an inlet of static blades of the turbine, said static
blades having said inlet, passages through which the heating fluid
passes formed inside the static blades and an outlet, and said
heating fluid delivered passes through the passages from the inlet
and flows out through the outlet.
A turbine according to still another embodiment, in an external
combustion turbine, has a feature that said working fluid heated
with the heating fluid is conducted to an inlet of static blades of
the turbine, said static blades having said inlet, passages formed
inside the static blades and an outlet of the passages, and said
heated working fluid passes through the passages from the inlet,
flows out through the outlet and then is fed into interspaces
defined between adjacent ones of the static blades to thereby act
on dynamic blades of the turbine to rotate the turbine rotor.
A turbine according to a further embodiment, in addition to the
feature of the turbine described in the previous embodiment, has a
feature that the working fluid having passed through the passages
of the static blades is introduced to a heater to be re-heated.
Therefore, since the working gas which passes through the static
blades and the dynamic blades is heated by the static blades, the
working gas expands nearly isothermally. This leads to an increase
in driving energy for the turbine.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a top plan view of a turbine as an embodiment of
the invention;
FIG. 2 illustrates a perspective view of an example of a static
blade used in a turbine according to the invention;
FIG. 3 also illustrates a system of a turbine embodied by the
invention;
FIG. 4(a) illustrates a top plan view showing an example of a
static blade, a dynamic blade and passages formed in the static
blade, and FIG. 4(b) illustrates a cross-section showing an example
of static blades and dynamic blades;
FIG. 5 illustrates a system showing another embodiment of a turbine
according to the invention;
FIG. 6 illustrates a system showing other different embodiment of a
turbine according to the invention;
FIG. 7 also illustrates a system showing a further different
embodiment of a turbine according to the invention;
FIG. 8 illustrates a top plan view of an example of a prior art
turbine;
FIG. 9 illustrates a system of an example of a prior art
turbine;
FIG. 10 illustrates a system of an example of a prior art external
combustion turbine; and
FIG. 11 illustrates a pressure-specific volume diagram of the
working gas in a turbine.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention and advantageous details will now be explained more
fully below with reference to exemplary embodiments and with the
aid of the accompanying drawings.
FIGS. 1, 2, 4(a) and 4(b) illustrate a turbine and its members
according to the invention, and FIGS. 3, 5, 6 and 7 illustrate
respectively a system relative to turbines embodied by the
invention. FIG. 11 is a diagram showing pressure-specific volume
relationship for comparing a turbine according to the invention
with a prior art one.
As shown in FIG. 1, air enters a compressor 1 through an inlet 5
and is pressurized at the compressor. The compressed air passes
through a passage 18 and an inlet 12 to a combustion chamber 2 in
which fuel sent through a fuel port 11 is burnt with the air to
generate a high temperature, high pressure gas. Said gas is then
introduced through a passage 24 and a collector pipe 19 to an inner
passages 43 formed inside the static blades and passes therethrough
to heat the static blades, and sequentially enters subsequent
collector pipe 19 along arrow 23, the inner passages 43 of
subsequent static blades and therethrough further subsequent
collector pipe, and the inner passages of further subsequent static
blades and so forth. The working gas finally flows out of the inner
passages 43' of the first static blades 15', enters the collector
pipe 19' and passes through an inlet passage 25 and interspaces
between adjacent ones of the first static blades 15', and therefrom
the working gas is jetted into the first dynamic blades,
sequentially passes through a series of the static and dynamic
blades and flows out as gas flow 6 through a duct 7. The dynamic
blades 16' and 16 rotate to drive the turbine rotor 8 as well as
the load.
FIG. 2 shows an example of the inner passages of a static blade in
which 20 denotes passages for the working gas. The working gas
enters the static blades 15 through an inlet 21 of the inner
passages of the static blades and discharges out of an outlet 22 of
the inner passages as shown by arrows. 47 Shows an area in which
said inner passages are not formed. In order for the working gas
flowing outside the static blades to be heated effectively, the
inner passages are desirably formed possibly adjacent the surface
of the blade.
FIG. 4(a) shows an elevational cross-section of an example of a
static blade in a turbine of the invention. This is arranged so
that the working gas in the collector pipe 19 is introduced to the
inlet 21 of the inner passages of the static blades from a
distributor 37, passes through passages 20, 35 and 20, flows out
through the outlet 22 of the inner passages and enters the
collector pipe 19 by way of collector 36.
FIG. 4(b) shows a circumferential cross-section of the dynamic
blades 16 and the static blades 15, in which arrow 44 denotes a
direction of rotation. This is in contrast with FIG. 4(a). In a
turbine of the invention, since it is needed to heat the working
gas efficiently in contact with the static blades, the surface of
the static blade will preferably be as large as possible. Heat
transfer between the static blade surface 45 and the working gas
passing through interspaces defined between adjacent ones of the
static blades is performed effectively because the surface 45 is
enlarged. (Relevant Japanese Pat. Appln. No.77976/1989)
FIG. 3 shows a system of a turbine according to the invention, in
which air introduced through the inlet 5 is compress to a high
pressure at the compressor 1 and heated at the combustion chamber
2. The heated air passes through the static blade heater 26 and
acts on the turbine rotor 8 to drive the load 10.
As shown in FIG. 5, the working gas flowing out of the combustion
chamber 2 is introduced to and passes through the static blade
heater 26', after that,enters a recombustion chamber 27' to be
heated again and thereafter is introduced to the turbine 3 to avoid
a considerable thermal drop of the working gas, which effects
enough expansion of the working gas so as to increase the turbine
output.
FIG. 6 shows a system of an embodiment of an external combustion
turbine according to the invention. In this system a heating gas
enters a heat exchanger 28 through an inlet 29 and flows out
through an outlet 30. A heating element 46 for the working gas is
heated in the heater 28 in which the working gas introduced there
through an inlet 34 is heated to a high temperature and leaves
there through an outlet 31 and conduit 47 to drive the turbine 3,
and flows out through the outlet 6. The working gas flowing out
through the outlet 6 is introduced again to the inlet 34 via
conduit 48 after passing through a cooler 32 and a compressor 33.
On the other hand, the heating gas flowing out through an outlet 38
of the heat exchanger 28 is introduced to the static blade heater
26 through conduit 49, passes therethrough, enters again the heat
exchanger 28 through conduit 50 and inlet 39 and discharges through
the outlet 30, thereby to keep the static, blades at a high
temperature to increase the turbine output.
FIG. 7 shows a system of our turbine, in which the working gas
brought in the static blade heater 26 is re-inserted to the heating
element 55 of heat exchanger 28 through conduit 51 and inlet 41 to
be heated and discharged through an outlet 31 and conduit 52 to act
on the turbine 3. After that, the working gas passes through the
cooler 32 and the compressor 33 and is introduced through conduit
53 to the working gas inlet 34' to be reheated in reheater 56 of
the heater and thereafter to the static blade heater 26 through an
outlet 40.
FIG. 11 shows a pressure-specific volume diagram of a turbine
according to the invention. As seen in the diagram, the working gas
in a prior art turbine is compressed from point A (pressure P1,
specific volume Va) to point B (P2, Vb) and then heated in the
combustion room from point B to point C (P2, Vc) with an expansion
of the gas. After that, while the working gas expands from point C
to point D (P1, Vd), work done by the working gas is represented as
an area ABCD. On the other hand, in a turbine of the invention, as
the working gas passed through the static blade heater 26, the
temperature of the working gas at the entrance of the first static
blades of the turbine is lowered from point C to point C', but the
expansion of the working gas causes along a slant line C'D' which
is similar to an isothermal process CD' in contrast with an
adiabatic process represented by CD, and therefore the area ABC'D'
is larger than the area ABCD.
As mentioned above, according to the present invention, the working
gas passes through the inner passages 23 of the static blades
almost without any pressure fall and thereafter is introduced to
the turbine. Also, the working gas is heated. during its expansion,
so that the expansion of the working gas is nearly isothermal
rather than adiabatic. Accordingly, since the pressure difference
seems to be almost the same, a turbine of the invention can do more
work than a prior art one, and thus the invention will realize an
efficient turbine.
In the turbine described in claim 1, working gas flowing out of the
combustion chamber is introduced to the inlet of the passages
formed inside the static blades and passes through the interior of
the static blades. The working gas which flows out of the outlet of
the passages of the static blades is fed into interspaces defined
between adjacent ones of the static blades to act on the dynamic
blades of the turbine so as to rotate the turbine rotor. As the
static blades are heated with high temperature gas, the surfaces of
the static blades are of a high temperature and serve to heat the
working gas passing through interspaces between adjacent ones of
the static blades. Although in a prior art turbine, the temperature
of the working gas which passes through interspaces between
adjacent ones of the static blades is lowered in its adiabatic
expansion and the gas which expands adiabatically from point C in
FIG. 11 is represented as CD, in a turbine according to the
invention the working gas is heated in contact with the static
blades and therefore the expansion of the working gas is
represented as nearly isothermal expansion line CD", so that its
expanded volume is increased by DD" more than the point D of a
prior art adiabatic expansion and work due to the expansion is
increased by a quantity corresponding to an area CDD" thereby to
increase rotary energy of the turbine and to feed more energy to
the load.
Otherwise, for example, by means that the inner passages of the
static blades are of uniform cross-section, a high temperature,
high pressure gas can pass through the passages almost without any
expansion. Accordingly, the working gas has a descent in
temperature at the first static blades of the turbine, while the
gas can enter the first static blades almost without a drop of
pressure. In this case, expansion process is represented as ABC'D'
and its area is larger than the area ABCD.
Also in the turbine described in claim 2, because the working gas
passing through said inner passages of the static blades provides
heat to the working gas passing through interspaces between
adjacent ones of the static blades, the temperature of the former
working gas is lowered. Thus, as shown in FIG. 5, by means that the
working gas leaving the heater 26 that heats the interior of the
static blades passes through the recombustion room 27 and enters
the static blade heater 26', the surfaces of the static blades are
always kept a high temperature thereby to heat thoroughly the
working gas passing through the interspaces of the static blades,
so that the working gas expands nearly isothermally and therefore
increases expansive work thereof to drive the turbine rotor more
efficiently. In this situation, the expansion process is
represented nearly as ABCD".
Furthermore in the turbine described in claim 3, by conducting high
temperature heating fluid in an external combustion turbine through
the interior of the static blades, the static blades are heated and
therefore expansion of the working gas is increased thereby to
increase the rotary energy of the turbine rotor.
In the turbine described in claim 4, because the working gas of
high temperature in an external combustion turbine, similar to the
case in the internal combustion turbine described in claim 1,
passed through the interior of the static blades thereby to heat
the working fluid passing through interspaces between adjacent ones
of the static blades, the working fluid expands nearly isothermally
and expansion of the working fluid is increased, which results in
an increase in the rotary energy of the turbine rotor.
Also, in the turbine described in claim 5, the working fluid of
which temperature has lowered after passing through the inner
passages of the static blades is heated again by a heater to
elevate the temperature of the working fluid, so that its expansion
process corresponds to CD" in FIG. 11 and its expansion is
increased thereby to enlarge the rotary energy of the turbine
rotor.
Although in a prior art it is required to elevate extremely the
temperature of the working gas in a combustion room in order to
increase the driving power of the turbine, according to the
invention more output of the turbine can be obtained by heating the
working gas by a quantity that corresponds to a descent in
temperature, without such an extreme elevation of temperature.
As described above, although a turbine of prior art is based on an
adiabatic expansion, a turbine of the invention adopts a nearly
isothermal expansion of the working gas. Therefore, where the
working gas is of the same pressure as well as of the same
temperature in both turbines, considerably more output can be
obtainable in a turbine of the invention.
Having now fully described the present invention, it will be
apparent to one of ordinary skill in the art that many changes and
modifications can be made without departing from the spirit or
scope of the invention as set forth herein.
* * * * *